Large capacity and high parameter opposite firing boilers are often affected by uneven wall temperature distribution on high-temperature heating surfaces,which affects their operational safety and economy. To solve this problem,it is usually necessary to carry out optimization of the pulverization system or over-fire air. However,due to the variation of wall temperature distribution with boiler operating conditions,the conclusion of a certain optimization cannot adapt to all operating conditions. Based on the principle of wall temperatureregulation,an intelligent control strategy for over-fire air was designed,and the inlet structure of the over-fire air device was optimized andequipped with an electric actuator. A high-temperature heating surface wall temperature intelligent control system was developed,aiming toachieve automation and intelligence of over-fire optimization. Experimental research was conducted on a 1 000 MW unit for the intelligent control system. The wall temperature distribution at the outlet of the high-temperature superheater and the variation trend of the deviation between the outlet steam temperature and the highest wall temperature of the high-temperature superheater and screen superheaterwere compared under different loads before and after the system was put into use. The average deviation between the outlet steam temperature and the highest wall temperature of the high-temperature superheater and screen superheater in different load stages was statisticallyanalyzed. The results show that under different loads,the system can automatically adjust the opening and swing angle of each over-fire airbased on the real-time wall temperature distribution of the heating surface,so that the wall temperature distribution of the heating surfacealong the furnace width direction tends to be average. Under different loads,the system can significantly reduce wall temperature deviation.The wall temperature deviation at the outlet of the screen superheater is reduced from 50 ℃ to 20-30 ℃ ,and the wall temperature deviation at the outlet of the high-temperature superheater is reduced from 20 ℃ to 12 ℃ . The system can significantly reduce the wall temperature deviation that increases due to load changes. The system can leveling O concentration while leveling wall temperature.

刘一(1991—),男,湖南浏阳人,工程师,硕士。E-mail:904263276@qq.com

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LIU Yi,ZHANG Xiuchang,CHEN Hong,et al.Development and application of an intelligent control system for wall temperature of high-temperature heating surfaces[J].Clean Coal Technology,2024,30(9):140-146.